Editing Polystyrene (section)

=== Production ===
Polystyrene is an [[addition polymer]] that results when styrene [[monomer]]s [[polymerization|polymerize]] (interconnect). In the polymerization, the carbon-carbon [[pi bond|π bond]] of the [[vinyl group]] is broken and a new carbon-carbon [[sigma bond|σ bond]] is formed, attaching to the carbon of another styrene monomer to the chain. Since only one kind of monomer is used in its preparation, it is a homopolymer. The newly formed σ bond is stronger than the π bond that was broken, thus it is difficult to depolymerize polystyrene. About a few thousand monomers typically comprise a chain of polystyrene, giving a [[Molar mass distribution#Number average molar mass|molar mass]] of 100,000–400,000&nbsp;g/mol.{{Citation needed|date=January 2021}}

[[File:Polystyrene formation.PNG|class=skin-invert|center]]

Each carbon of the backbone has [[tetrahedral geometry]], and those carbons that have a [[phenyl group]] (benzene ring) attached are [[chirality (chemistry)|stereogenic]]. If the backbone were to be laid as a flat elongated zig-zag chain, each phenyl group would be tilted forward or backward compared to the plane of the chain.{{Citation needed|date=January 2021}}

The relative [[stereochemical]] relationship of consecutive phenyl groups determines the [[tacticity]], which affects various physical properties of the material.<ref>{{Cite web |date=2013-10-02 |title=The Phenyl Group |url=https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Arenes/Properties_of_Arenes/The_Phenyl_Group |access-date=2022-06-18 |website=Chemistry LibreTexts |language=en}}</ref>